U.K. prosecutors will call a senior procurement officer from ConocoPhillips as a key witness in the London trial of four individuals charged with bribery to secure business related to the Jasmine gas field in the North Sea.

The U.K.’s Serious Fraud Office has charged four people for allegedly making or accepting illegal payments to ensure that logistics and freight operations company F.H. Bertling won contracts from, the operator of the Jasmine field. The alleged conspiracy took place between January 2010 and May 2013.

During his opening argument, the SFO’s counsel said Tuesday that ConocoPhillips’ Dave Moloney employed Georgina Ayres as a senior contract specialist in 2010. Ms. Ayres, a defendant in the case, allegedly accepted bribes from executives at F.H. Bertling Ltd. to ensure the company got freight-forwarding contracts from ConocoPhillips worth approximately £6.5 million.

The energy industry is fertile ground for corruption because much oil and gas exploration occurs in developing countries, with significant involvement of government officials, and because of the industry's reliance on third-party providers. Three of the 10 largest settlements under the U.S. Foreign Corrupt Practices Act were made with oil-related companies, and one of the largest corruption probes ever involves Brazil's state oil producer Petroleo Brasileiro S.A.

ConocoPhillips, the operator of the Jasmine field, isn’t facing any charges in the case.

The SFO’s counsel told jurors that Mr. Moloney’s testimony in coming weeks will likely describe Ms. Ayres as a “resilient and resourceful” professional who became his “number two” in the procurement for the Jasmine project.

ConocoPhillips’ procurement systems are designed to prevent any one person having undue influence in the process, the prosecutor said of the witness’s eventual testimony.

The SFO expects Mr. Moloney to say any meeting between Ms. Ayres and executives from prospective service providers would have been inappropriate, that he never authorized such meetings and that, had he known of any meetings, Ms. Ayres’s contract would have been terminated and F.H. Bertling’s bid disqualified.

Another defendant in the case is Colin Bagwell of Houston, Texas, who served as F.H. Bertling’s chief commercial officer between April 2007 and October 2011. The prosecution claims Bagwell was the mastermind of the scheme and held meetings with Ms. Ayres. Mr. Bagwell is facing two counts of conspiracy to pay bribes.

The SFO also charged Peter Smith, a former F.H. Bertling director, and alleges that he was in charge of making the payments to the agents. Mr. Smith set up a company in the United Arab Emirates that issued fake invoices for consultancy services to F.H. Bertling, the SFO said. Those payments were then allegedly redirected to Ms. Ayres.

The fourth defendant is Robert McNally, a freight forwarding agent who prosecutors say was “the middleman.” The SFO says Mr. McNally facilitated the contact between Ms. Ayres and Mr. Bagwell.

Two other company directors charged in this case, Stephen Emler and Giuseppe Morreale, have pleaded guilty to the charges of making corrupt payments to ConocoPhillips agents.

The jury trial of the individuals began last week at Southwark Crown Court and is expected to last five to six weeks. In opening arguments this week, the SFO is disclosing documents and emails to show the contacts and communications among those charged.

In an emailed statement, ConocoPhillips said it is aware of the ongoing trial and directed questions about the case to the SFO.

This is the second corruption case the U.K. agency has brought against F.H. Bertling. The SFO in 2016 charged the company, along with seven current and former directors, with one count each of making corrupt payments to an agent of the Angolan state oil company, Sonangol. Three of the defendants were found guilty and paid a fine to the SFO, three pleaded guilty and one was acquitted. The company pleaded guilty.

F.H. Bertling has closed its U.K. operations in light of the SFO’s investigations into the firm. Its parent, Bertling Group, said in a statement that the U.K. entity was sold and disbanded in January 2017.

Bertling Group is a 150-year-old shipping and logistics company based in Hamburg, Germany. The private company has at least 60 subsidiaries in 35 countries and 850 employees.